41733-27-1 Cyclic(glycylglycyl-L-valyl-L-prolylglycylglycyl-L-valyl-L-prolylglycylglycyl-L-valyl-L-prolyl) Cyclo(L-val-gly-gly-L-pro)3 Cyclo(L-valyl-glycyl-glycyl-L-prolyl)3